A bullet was fired through the window of a Brooklyn synagogue Saturday, sources said.

The round ripped into the Kahl-Zichron-Mordechai Synagogue on Nostrand Avenue in Midwood shortly before 3 p.m., according to surveillance video reviewed by police.

The bullet hole in the first-floor window was spotted around 10 p.m., the sources said.

A bullet fragment was found inside but no injuries were reported — the synagogue was closed at the time of the incident.

Police have not identified a culprit.